Means for automatically closing furnace doors



May 5, 1925. 1,536,160

R. W. STEWART MEANS FOR AUTOMATICALLY CLO SING FURNACE DOORS Filed Feb. 21, 1922 INVENTOR Robnwsww v a mam-Tn Patented May 5, 1925.

UNITED STATES PATENT OFFICE.

ROBERT W. fiTE'WART, OF FINDLAY, OHIO.

MEANS FOR AUTOMATICALLY GIIOSING FURNACE DOORS.

Application filed. February 2;, 1922. Serial No. 538,361.

fuel. WVhen coal is first supplied to a fire a large quantity of air isnecessary to promote the proper combustion of the gases that are early expelled from it. As combustion proceeds the need for air for this purpose grows gradually less hence it is desirable thatthe air admitting door or doors be gradually closed. The proper closing of the door or doors may consume from five to fifteen minutes hence it is desirable to provide means whereby the closing of the door maybe elfected without personal attention during all the time required. The object of the invention. therefore, is to provide means whereby such or similar doors may be automatically and graduallyclosed.

The invention is embodied in the example herein shown and described, the features of novelty being finally claimed.

In the accompanying drawings Figure 1 is an elevation of the front of a furnace with an isometric extension of the side showing my invention applied thereto.

Fig. 2 is an elevation of the clock or escapement mechanism with parts broken out looking toward the right of Fig. 3.

Fig. 3 is an edge view of what is shown in Fig; 2, with parts broken out.

In the views the furnace 5 has its ash pit at 6 and fire chamber at 7 above the grate. An. opening for feeding fuel is shown. as closed by a door at 8. The fire chamber also has opcnings9 and. 9* for admitting air above the fuel said opening being closed by a hinged door like that shown at 10 adapted to close by gravity. The extent of opening of the door is limited by an adjustable stop 10*. Connected with the door 10 is a suitable flexible member in the form of a cord, chain or wire 11 passed provided with a weight 16 to hold it fric tionally. engaged with the drum. The weight of the door 10 prepo-nderates the weight 16 and if that door he raised or opened and then released it will close and rotate the drum 14. When the door is raised the weight 16 islowered but thedoor may be opened by pulling down said weight it being obvious in either case that the cord 11 will necessarily slip on the drum 1% because that member is held stationary by the pawl 18. The drum has afiixedto one end thereof a ratchet wheel 17 engaged by a pawl 18 on the side of a large gear wheel 19 said pawl being held in yielding engagement with the ratchet by means of a spring 20 pressing on the pawl. The

large gear wheel 19 engages a pinion 21 on a shaft 22 journaled in the frame pieces 15 and '15. On one end of the shaft 22 is secured an escapement wheel 23 engaged by the crutch 2d fixed to the upper end of a pendulum 2 5. I The pendulum and the crutch are pivoted upon a carrier arm 26 pivoted at 27 to the frame piece 15 so that one end of the carrier arm can be raised or lowered for the purpose of changing the I operative relation of the pallets of the crutch to the escapement wheel 23. If the pendulum weight 30 supported on adjust able pin 31 be raised the speed of release is increased and conversely. The frame plate 15 is provided with a number of holes 281 through a selected one of which and a hole in the carrier arm a pin 29 is passed to hold the pendulum and escapement lever in the position to which adjusted.

Several doors may be simultaneously operated by a single escapement apparatus as illustrated by the cord running over pulleys 12 and 15 to a door like the door shown at 10 for closing the opening 9. In a such case the cord, chain. or wire running over pulleys 12 and 13" is united with. the flexible member 11 at a suitable point above the drum 14:. i

Just before or inintlediately when fresh coal. is supplied to the bed of hot coals the door or doors are raised by pulling down on cord of weight 16 as far as desired after which the pull of the weight of the door tends to rotate the escapement wheel and therefore to oscillate the pendulum the os- I cillations of the latter controlling the speed of rotation of said wheel; The time in which a door shall close may therefore be regulated in two ways first by the extent io'which the door is raised and second by varying the time of oscillation oi? the pendulum as hereinbei'ore set forth.

The forms of the parts, can be changed without departing from the gist of the invention as claimed;

lVhat I claim is:

1. In combination with a combustion chamber having an air inlet, a gravity actuated door to close the same, a flexible member connected at one end to said door, a weight on the other end of said flexible member of less weight than the weight of the door, a drum around which the flexible member is coiled between said weights in slipping frictional engagement with the drum to drive the latter by the weight of the closing door, an escap'ement mechanism including an escapement wheel driven by said drum and a pendulum having acrutch engaging the escapement wheel for gradually closing the door, substantially as described.

2. In combination with a combustion chamber having an air inlet, a gravity actuated door to close the same, a flexible member connected at one end to said door, a weight on the other end of said flexible member ot l'ess weight than the weight of the door, a drum around which the flexible member is coiled between said weights in slipping. frictional engagement with the drum to drive the latter by the weight of the closing door, an escapement mechanism including an escapement wheel driven by said drum and a pendulum having an adjust-able crutch engaging. the escapement wheel 'For gradually closing the door, substantially as described.

3. In combination with a combustion chamber having an air inlet, a gravity actuated door to close the same, a flexible member connected at one end to said door, a weight on the other end of said flexible mem ber of less weight than the weight elf the door, a drum around which the flexible member is coiled between said weights in slipping frictional engagement with the drum to drive the latter by the weight of the closing door, means to prevent the rotation of the drum in one direction, an escapement mechanism including an escapement wheel driven by said drum and a pendulum having a crutch engaging the escapement wheel "for gradually closing the door, substantially as described.

4. In combination with a combustion chamber having an air inlet, a gravity actuated door to close the same, a flexible member connected at one end to said door, a weight on the other end of said flexible member of less weight than the weight oi? the door, a drum around which the flexible memberis coiled between said weights in slipping frictional engagement with the drum to drive the latter by the weight of the closing (1001, an escapement mechanism including an escapement wheel driven by said drum and a pendulum having a crutch engaging the escapem'ent wheel for gradually closing the door and an adjustable carrier arm on which the crutch and pendulun'i are pivoted, substantially as described.

ROBERT \V. STEXVART. 

